Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Ductile materials for Arctic conditions

06.01.2015

The production of oil and gas at temperatures between 40 and 60 degrees below zero means that researchers must advance the development of materials that can withstand these harsh conditions.

The oil industry is heading north. It is said that 30 per cent of remaining gas, and 13 per cent of remaining oil, reserves are to be found in the Arctic. We're talking about billions.


In the even In Artic steel constructions must be able to withstand temperatures as low as minus 60 degrees. Photo: Ragnhild Lundmark Daae, NTNU

The Snøhvit and Goliat projects are being developed for operation in temperatures of minus 20 degrees. In the even harsher conditions further north, steel constructions must be able to withstand temperatures as low as minus 60 degrees. But our current materials are not tough enough, because when temperatures fall below minus 20 degrees, the steel becomes brittle and more likely to fracture.

Tests, tests and more tests

Senior researcher Odd Magne Akselsen is heading a group at SINTEF Materials and Chemistry whose aim is to enhance the fracture resistance of construction materials. The idea is to develop precise mathematical models, predict materials properties and make the necessary modifications. To achieve this they need a lot of information at both micro- and nannoscales.

"There are two factors", says Akselsen. "The ductility (fracture resistance) of a material is dramatically reduced when temperatures fall below zero", he says. "Moreover, steel plates used in platform construction have to be welded together. After welding, involving high rates of heating and cooling, it becomes easier for cracks to develop", he says.

– And just one crack is dangerous?

"A single crack can result in brittle fracture by which the material breaks in two in just a couple of seconds", says Akselsen. "Such fractures are unstable, impossible to predict and very dangerous – potentially resulting in catastrophic accidents.

In order to avert such hazards, the researchers are carrying out numerous tests involving the flexing and stretching of cracks inserted into welds, followed by the examination of small samples using an electron microscope.

Does a crack make a noise?

The researchers are currently testing a new technology that involves taking measurements using acoustic signals. They attach a sensor and sound heads to the samples while they deform and stretch them.

"We record a small signal when the crack begins to develop", says Akselsen. "It's like the sound of breaking glass.  We stop the test at the first indication of a sound, and put the sample under the microscope to find out where the signal has come from. Even though this may occur in a small grain just a few micrometres across, we enlarge everything to let us see where the microfracture was initiated", he says.

– And then?
"Yes, then we can find out why it happened, and then look into how we can make modifications to prevent it.", says Akselsen.

Shifting the ductility curve

Akselsen is a "greybeard" with extensive experience in the world of materials science. He is the enthusiastic senior scientist generating passion for the work among the younger aspiring researchers in his team.

He is now talking a lot about the "ductility" or "transition" curve which determines at what temperatures a material changes from being ductile to brittle.

"Somehow we have to find a way to shift this curve towards a lower temperature range", says Akselsen. "This is incredibly complex work, but we believe we're on the right track", he says.

It is a major advantage having NTNU participate in the project with a number of its Ph.D. and Master's students. Akselsen reveals that a female Master's student has recently succeeded in introducing a crack exactly where researchers wanted it in a sample of test material only a few micrometres across.

"This is incredibly valuable work", says Akselsen. "So now we know how the brittle phase will behave under deformation", he says. "Studying local strength and ductility properties at this level allows us to develop more accurate models which can be used to predict unwanted incidents", he explains.

Aluminium is also being tested

Aluminium will also be tested as part of this project to see if it can be adapted for use under Arctic conditions.

It can be used to construct accommodation modules, gangways and staircases installed on platforms. Because aluminium is lighter than steel, it can generate weight savings during the transport of subsea components from the mainland into Arctic waters.

There are many issues that remain unresolved. The researchers are well aware that improvements in quality will be needed when the oil industry starts to produce hydrocarbons north of the Goliat field.

"The lower temperatures mean that there is a risk that only 80 per cent of the strength of current steel products can be utilised", says Akselsen. "If we are to succeed in shifting the ductility curve down to 50 degrees below zero, basic materials must be modified to provide an adequate ductility margin", says Akselsen.

"Our task today is to consolidate our know-how and testing methods, and accumulate test results. This will be a valuable foundation which the oil and gas industry can use as a guide", he says.

http://www.sintef.com

Aase Dragland | AlphaGalileo

Further reports about: Arctic SINTEF conditions construction cracks fracture materials modifications temperatures

More articles from Materials Sciences:

nachricht An innovative high-performance material: biofibers made from green lacewing silk
20.01.2017 | Fraunhofer-Institut für Angewandte Polymerforschung IAP

nachricht Treated carbon pulls radioactive elements from water
20.01.2017 | Rice University

All articles from Materials Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Traffic jam in empty space

New success for Konstanz physicists in studying the quantum vacuum

An important step towards a completely new experimental access to quantum physics has been made at University of Konstanz. The team of scientists headed by...

Im Focus: How gut bacteria can make us ill

HZI researchers decipher infection mechanisms of Yersinia and immune responses of the host

Yersiniae cause severe intestinal infections. Studies using Yersinia pseudotuberculosis as a model organism aim to elucidate the infection mechanisms of these...

Im Focus: Interfacial Superconductivity: Magnetic and superconducting order revealed simultaneously

Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.

While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...

Im Focus: Studying fundamental particles in materials

Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales

Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...

Im Focus: Designing Architecture with Solar Building Envelopes

Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.

As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Sustainable Water use in Agriculture in Eastern Europe and Central Asia

19.01.2017 | Event News

12V, 48V, high-voltage – trends in E/E automotive architecture

10.01.2017 | Event News

2nd Conference on Non-Textual Information on 10 and 11 May 2017 in Hannover

09.01.2017 | Event News

 
Latest News

Helmholtz International Fellow Award for Sarah Amalia Teichmann

20.01.2017 | Awards Funding

An innovative high-performance material: biofibers made from green lacewing silk

20.01.2017 | Materials Sciences

Ion treatments for cardiac arrhythmia — Non-invasive alternative to catheter-based surgery

20.01.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>